Javelin Oil Pump

[Moises]

Good afternoon: I've tested the oil pump on my Javelin again. Previously, I replaced the drive spindle with one supplied by Paul Beaumont (J.C.S.). I've attached a YouTube link to the video I recorded. As always, I would appreciate your valuable feedback. Is it normal for the oil pressure gauge to fluctuate when the engine speed increases?

Thank you very much, and Merry Christmas and a Happy New Year!

https://youtu.be/XJ_HP24J02k?si=RwE91gLxkn1ExSQ6

[PJGD]

Could the gauge fluctuations be due to the regulator valve operation? The set-up that you have there has a very small volume which will not provide much damping to the system, so the pressure will respond very rapidly (at high frequency). On engine, the system volume is much greater which will provide significant damping.

You could try putting a small diameter rod into the regulator valve adjusting screw so that it rests against the valve but sticks out of the adjuster enough that you can feel what the valve is doing. You should be able to feel when the valve is working. It would mean getting your hand very oily, so wear a neoprene glove!

[Forumadmin]

The pump is rotating at half crankshaft speed so your 1900 rpm is actually 3800 rpm. The pump should produce 60 psi at 1000 rpm (indicated 500rpm) at operating temperature and with an unworn engine. It is the flow rate which is hard to establish for test purposes but your bypass valve should give a good feel for what is accepable. My educated guess is that an oriface of between 3 and 4 mm would provide about the correct flow. So, having set the bypass oriface to that size, I would expect the oil pressure to rise as rpm increases to 60 psi at 500 rpm and then to level out to the pressure release valve setting (70 psi) above that. There will be oscillation as the valve opens and shuts because there will be bounce in the spring. Pressure waves in the fluid because of reflections between the valves (similar to exhaust notes or water hammer in domestic water systems) would also cause oscillations. Listening to the strain on the pump when you close the valve indicates to me the pump gears are good. Check there are no air bubbles in the oil coming out of the pump indicating a poor seal between body and cover.

[Moises]

Thank you Philip and Keith